The United States is going to be whiter on Christmas than it has been so far in a generally mild December.
But it doesn’t appear likely the New River and Roanoke valleys will be part of that.
Historically, about 10 percent to 15 percent of Christmases are white in our region. However, two of the past three have been, following the National Weather Service definition of having at least 1 inch of snow on the ground.
As of Tuesday, about one-third of the nation had snow cover. Snow has been abundant in the Pacific Northwest and northern Rockies, battered by a series of storm systems. Snow cover has also spread over the Northern Plains and Northeast.
A year ago at this time, about a quarter of the U.S. was covered by snow, so this winter has finally caught up and passed last year. The four winters before that had about 50 percent snow cover nationally by this time.
A storm system this week will add snow cover to parts of the Central Plains and Upper Midwest from Kansas and Nebraska to Wisconsin.
Many cities in that region, such as Omaha, Des Moines and Chicago, will see the end of record streaks of snowless days, topping 280 days.
Those streaks are the result of a record warm March cutting off the snow season early last winter and a mild December delaying the start of it this winter.
The last measurable snow many of those locations saw was from the same system that gave Roanoke its last measurable snow.
An Alberta clipper moving southeastward gave Roanoke 0.2 inch of snow and Blacksburg 1.1 inch on March 5.
But we are not close to any snowless streak records. Roanoke’s entire 1919-20 winter was snowless, and Blacksburg got 0.6 inch from Superstorm Sandy on Oct.29-30.
The system bringing the snow to the Midwest will introduce the coldest shot of Arctic air we’ve seen this season today, Friday, which could at least scatter some snowflakes in the 50 mph blustery wind gusts Friday.
Beyond some higher elevations, locations closer to the West Virginia border, or anyone who happens to get under a heavier snow squall for a little while, it’s unlikely to whiten the ground, and more unlikely that it will stay white through Christmas.
The days after Christmas, however, have the potential to produce a major storm system that will deeply whiten some portion of the central or eastern U.S.
It’s too early to tell exactly where that will be, though early returns favor somewhere west of us. There are some weather features in Canada that may block the storm and force it farther south, however, so it’s worth keeping an eye on.
Each new storm system that spreads white farther south and east increases the chance of cold temperatures holding in longer, and of the next storm system being white farther south and east still.
A white day is probably not far away for Southwest Virginia, but this likely won’t be the third white Christmas in four years.

• Kevin Myatt writes “Weather Journal” for The Roanoke Times. To check on the latest updates to his Christmas Day forecast, visit blogs.roanoke.com/weatherjournal.